NYX - Eiger integration into flyer code

[JunAishima]

This will be the main server-side code work for #166

Note that the Eiger2 detector looks the same to EPICS as the Eiger (1). The Simplon API is the same, which means that the IOC will have the same interface for AreaDetector, which means the Ophyd object is the same (there is only one for Eiger and Eiger2).

The files created are also the same organization - filename_master.h5 and one or more filename_number_data.h5, where number is zero-filled six-digit number (so 1 is 000001).